To Tom Barr or any other PMDD specialists: I'm going to be dosing my
aquarium with potassium nitrate, potassium sulfate, and potassium phospate.
Right now I can only get potassium nitrate (I can't get the others locally
but will within the next few weeks). Can I just add potassium nitrate alone
to the aquarium without the others?

Yes. A lot of people do. Just keep an eye on your nitrate levels. You don't
want to increase them too much, too fast.